Earth, wind and firefly: A night chasing rare lightning bugs
If you told 7-year-old me that I’d catch fireflies for work, I would not have believed you. Yet I am #winning because that’s exactly what I did this summer.
Just as dusk set in on a Delaware beach, I talked with Jason Davis of the Delaware Division of Fish and Wildlife, who was gearing up to catch fireflies in waders and a headlamp, holding a butterfly net. Besides immediately feeling unprepared in my cropped cargo pants and T-shirt, I was curious to learn more about why these fireflies were so special.
I quickly learned that Jason was not just catching any firefly — he was on the hunt for the elusive Bethany Beach firefly, which lives among other fireflies in only a small stretch along Delaware’s Atlantic coast beaches.
The Bethany Beach firefly was put on our radar earlier this year, when the Center for Biological Diversity and Xerces Society for Invertebrate Conservation petitioned the Service in May 2019 to emergency list the firefly under the Endangered Species Act. We reviewed the petition and decided that we do need to complete an in-depth status assessment under the normal listing process to determine if the species is threatened or endangered. We announced today that we will do that assessment. We won’t know when we will complete it until the assessment is incorporated into our national workplan, which looks five years out or more.
In the meantime, we recognized the need to get more good data, and worked with the Delaware Division of Fish and Wildlife to support their survey efforts. We sent along help from our at-risk species conservation fellows, who helped us monitor other species across the Northeast this summer including the frosted elfin and saltmarsh sparrow.
The Bethany Beach firefly was first discovered in 1949 by Frank Alexander McDermott. Surveys for it haven’t been done since 1998, when it was found in only seven swales out of 18 that were surveyed at the time. If you’re wondering what a swale is, I’ve got you covered: it’s a marshy depression located behind dunes surrounded by woody marsh vegetation which is where all of these fireflies hang out. To get a sense of the Bethany Beach firefly’s distribution across Delaware, biologists surveyed almost 80 swales this summer.
Lack of surveys aren’t the only reason scientists are on the lookout for this firefly. “The species only occurs in Delaware so far as we know,”Jason told me. “And right now, these fireflies are facing threats such as sea-level rise because their habitat is close to the ocean.”
He pointed out additional threats to the firefly including coastal storms, invasive species like phragmites or other insects, and light pollution, which can diminish the green double flash that this firefly uses to communicate with others. Even that night, there was question over flashes seen in the distance and whether it was the Bethany Beach firefly.
“There’s definitely something flashing over there,” Jason said to Ryan and Joe, two of our summer at-risk species conservation fellows, who were assisting Jason with these surveys. “Actually, that could have been a car, I don’t know,” he said as we walked towards the flashing lights.
If you haven’t ever been to Bethany Beach or coastal Delaware, let me paint this picture for you. Just on the other side of a shrub-filled dune was a two-way state highway with cars and their bright lights zipping by, and the dark night sky lit up every once in a while when a plane flew overhead. It’s definitely a feat to spot and catch these fireflies.
There’s something else you should know about fireflies, including the Bethany Beach firefly (those within the Photuris species complex). The females can be brutal. They prey on males of other firefly species.
In general, a male firefly lights up to signal that he’s looking for a female mate, and if he’s lucky, a willing female will respond. Some males aren’t so lucky. The female Bethany Beach firefly will mimic the signal of a female from another species to lure in the male. Then she eats him. He’s her source of toxin to protect herself and her eggs from predators.
While the mimic behavior may mean life or death for fireflies, it also complicates things for biologists. It means they have to catch and measure fireflies to confirm the species.
Using butterfly nets, Jason, Ryan and Joe looked out for the signature double flash of the Bethany Beach firefly and then swung their nets in hopes of physically capturing the moving flash they had just seen. Luckily, we (or really, they!) caught two in about 15 minutes and proceeded to measure them and look for specific markings that indicate the firefly is likely the species we were looking for. After some measuring and photos, Jason confirmed they’re bethaniansis. Check out the photo below to see how to confirm a firefly is a Bethany Beach firefly.
As Jason released the fireflies and started to pack away his materials, I asked him his thoughts on why any of us, those working in conservation and those who don’t, should care about the plight of these fireflies- what does this mean for people?
“From a wildlife conservation standpoint, it’s part of our natural biodiversity. Conservation of biodiversity is something that we all need to really invest in because it’s really our future. We don’t know what we lose if we lose the firefly,” Jason said. “The other thing is that fireflies are probably the one species of insect that can excite kids and connecting kids with nature is huge, especially with today’s technology. Kids aren’t excited to go catch cockroaches, but fireflies are fun.” I couldn’t agree more!
Tylar Greene is a Public Affairs Specialist with the North Atlantic-Appalachian Region.
